Question

I am trying to use validates_timeliness to ensure that SliderImage.start is always before SliderImage.stop:

class SliderImage < ActiveRecord::Base

  validates_datetime :start, :stop
  validates :start, :timeliness => {:before => stop}

end

But of course stop is not defined yet. How can I accomplish this?

Answer 1

The stop value must be called on the record object being evaluated. The shorthand version is pass the symbol :stop, and this be assumed to be method on the record which will called at validation time.

Otherwise you can use a lambda like so

lambda {|r| r.stop } 

I would tend to write your validation as

validates_datetime :start
validates_datetime :stop, :after => :start

p.s. I’m the plugin author 🙂